Marine and Farallon Island Program

Storm-petrel decline

Of the Ashy Storm-petrel's worldwide population, some 60% breeds
at Southeast Farallon Island (SEFI). Concerned that the Farallon population of this
diminutive relative of albatrosses might warrant federal listing as "threatened," PRBO this
year prepared a new analysis of the Ashy's status at the island. Comparing 1971-72
estimates of its breeding population on SEFI with data obtained in 1992, we found an overall
population decline of about 35% over the 20-year period and a decline in breeding birds of
about 40%. According to Farallon research director Bill Sydeman, the actual amount of the
decrease is uncertain, due to factors including oceanographic differences (which likely
affect storm-petrels' breeding) between 1972 and 1992. Our recommendations include a
call for further research on the Ashy's population size and status and also planning a
recovery program that might employ nest boxes (see Observer 107) to enhance the birds'
nesting success and help secure important breeding grounds for the Ashy Storm-petrel at
SEFI.

Contaminant findings

In July 1996, we submitted to the Gulf of the Farallones National
Marine Sanctuary our final report on levels of organochlorine pesticides and trace metals
found in seabirds, marine mammals, and their prey. Major findings: highly elevated levels
in northern sea lions (less so in Common Murres) of DDE and PCBs; and moderately high
levels of mercury in sea lions and Pigeon Guillemots. Although murres and sea lions
appear to be subject to elevated contaminant loads, the levels have decreased substantially
over the past 20 years. Copies of the report (of which chapters are being published in
scientific journals) are available from PRBO for $40.

Alcatraz Island

Under a recently completed long-term cooperative agreement with Golden
Gate National Recreation Area, PRBO has begun monitoring seabird populations on
Alcatraz Island. Biologist Nathan Fairman visited "The Rock" throughout the breeding
season, focusing on Brandt's and Pelagic cormorants, Western Gulls, Black
Oystercatchers, and Pigeon Guillemots. The Brandt's Cormorant colony, newly
established in 1993, already contains over 200 breeding pairs, and reproductive success for
this species was considerably higher on Alcatraz this year than it was on SEFI, suggesting
that the birds in San Francisco Bay have found a new and reliable food source. Goals for
this ongoing project include assessing the influence of human disturbance on the
cormorants and other wildlife: more than a million people currently visit Alcatraz each
year!

Oil Spill Seabird Restoration

We initiated studies in 1996 on SEFI as part of a $5 million
settlement for damages from the Apex Houston oil spill (see Observer 101, Fall 1994). Our
aim is to help assess population trends for the Common Murre in California and elsewhere
along the west coast, and to interpret a restoration effort at Devil's Slide Rock being
conducted by the U.S. Fish and Wildlife Service (USFWS). PRBO's role, carried out by
Farallon biologist Michelle Hester and project directors Bill Sydeman and Nadav Nur, will
include investigating year-round murre colony attendance patterns, developing correction
factors to convert counts of individuals to estimates of breeding pairs, and other activity.
As in the past, our commitment to long-term research in cooperation with USFWS on the
Farallones forms the backbone of this project: it enables us to understand seabirds
population changes in relation to variability in the marine environment.

Coastal and Estuarine Research

Snowy Plovers at Point Reyes

Due primarily to PRBO's effort to protect and monitor nest
sites, Snowy Plovers at Point Reyes National Seashore fledged four times as many chicks
in 1996 as in 1995. In a project supported by PRBO members, staff biologist Catherine
Hickey and coastal program director Gary Page worked with the Park Service to place
exclosures around plover nests.

These prevented predators such as the Common Raven
from taking the plovers' eggs. Signs on the beach helped educate people about the birds'
vulnerability to disturbance. Fifteen chicks reached fledging compared with only four in
1995. PRBO gained experience protecting a threatened species and strengthened our
partnership with the National Park Service. We will continue this effort to both increase the
number of locally nesting Snowy Plovers above the point of no return and to evaluate
management techniques that can help the species recover.

Snowy Plovers at Moss Landing

New records were set in 1996 in our long-term study of
Snowy Plovers in the Monterey Bay area. Approximately 365 chicks hatched, about 75
more than in 1995, and approximately 141 fledged, compared to a previous high of 120
(these findings are preliminary). The increase is due in part to continuing collaborative
efforts, by PRBO and several public agencies, to use exclosures to protect Snowy Plover
nests from predators. Also, a new management effort in 1996 at Moss Landing,
spearheaded by PRBO staff biologist Doug George, succeeded dramatically. With the
permission of California Department of Fish and Game, we manipulated water levels in the
salt ponds to produce the highest quality habitat for plover nesting and brood survival. Of
the 141 Snowy Plover fledglings from Monterey Bay area, 59 came from successful nests
at Moss Landing salt ponds. The new methods are adding to our ability to take effective
action for the recovery of a native nesting shorebird.

Latin America

Bird Conservation and Genetics

In a project developed jointly with San Francisco State
University (SFSU), PRBO is investigating where in the tropics various populations of North
American breeding birds spend the winter. Collaborating with Dr. Tom Smith, a PRBO
board memeber and scientist with the SFSU Conservation Genetics Laboratory, we use
genetic markers to discern slight differences in the makeup of bird populations.
Determining which of California's migratory songbirds winter in the dry tropical forests of
western Mexico, the highlands of Honduras, or the Costa Rican cloud forests will greatly
advance our understanding of the demographic factors that regulate these populations, both
in the breeding and wintering grounds. Our 1996-97 project will utilize student field
biologists from El Salvador and Honduras, providing them with intensive training in bird
identification and mist-netting techniques.

Training in Yucatan

Building on successful programs in Mexico, Costa Rica, and Panama,
this winter PRBO will lead a course in the Yucatan for Latin American students and
technicians, the first such training offered in southeastern Mexico. Collaborating with the
Canadian Wildlife Service and Universidad de Campeche, PRBO biologist Borja Mil&aagrave; will
help direct the two-week course at Calakmul Biosphere Reserve in the southern Yucatan
peninsula.

Las Joyas Volunteers

Starting in mid-November 1996, experienced PRBO field biologists
are volunteering for three months at Mexico's Las Joyas Field Station (see Observer 106).
assisting in avian monitoring efforts at Sierra de Manatlán Reserve. Support for this
international exchange of expertise came from our generous sponsors who pledged
contributions to Rich Stallcup's Bird-a-Thon count this year. Muchas
gracias!